Inking system with means for milling hydrophobic liquid into water miscible ink film

ABSTRACT

An inking system is provided for a duplicating master, of a type wherein the nonimage portions are selectively repellent to wateror glycol-based inks and the image portions accept water or glycol-based inks. The water-based ink is applied to the printing rollers of a printing press, in the usual manner. A small quantity of a hydrophobic liquid is dropped on one roller of the train of rollers of the printing press, ahead of the roller which directly applies ink to the printing master. This liquid is milled into the ink by the rolling action of the rollers. The end result is that the image areas of the printing master accept that water-based ink and the nonimage areas reject the water-based ink.

United States Patent [72] Inventor Bernard Kaminstein Paramus, NJ. [21] App]. No. 807,325 [22] Filed Mar. 14, 1969 [45] Patented Sept. 28, 1971 [73] Assignee Inc. C. Olivette & C. S.p.A.

Ivrea, Italy [54] INKING SYSTEM WITH MEANS FOR MILLING HYDROPHOBIC LIQUID INTO WATER MISCIBLE INK FILM 2 Claims, 4 Drawing Figs.

[52] U.S. C1 101/148, 101/366, l01/452 [51] Int. B4lf7/32, 1341f 7/36 [50] Field of Search 101/452, 451,450,147, 148, 132.5, 366

[56] References Cited UNITED STATES PATENTS 2,530,282 11/1950 Brodie et a1. 101/350 1,669,416 5/1928 Huebner 101/456 1,854,719 4/1932 Stephenson 101/452 X Primary Examiner.l. Reed Fisher Attorney-Lindenberg and Freilich ABSTRACT: An inking system is provided for a duplicating master, of a type wherein the nonimage portions are selectively repellent to wateror glycol-based inks and the image portions accept water or glycol-based inks. The water-based ink is applied to the printing rollers of a printing press, in the usual manner. A small quantity of a hydrophobic liquid is dropped on one roller of the train of rollers of the printing press, ahead of the roller which directly applies ink to the printing master. This liquid is milled into the ink by the rolling action of the rollers. The end result is that the image areas of the printing master accept that water-based ink and the nonimageareas reject the water-based ink.

SOLENOID INKING SYSTEM WITH MEANS FOR MILLING I-Ir'DROPHOBIC LIQUID INTO WATER MISCIBLE INK FILM BACKGROUND OF THE INVENTION This invention relates to inking techniques for a lithographic-type printing master, and more. particularly to improvements therein.

In an application by this inventor, bearing Ser. No. 668,262, filed June 12,1967, and entitled, Method and Means for making a Duplicating Master," there is described an arrangement wherein an electrophotographic copy can be converted into a printing or duplicating master. The electrophotographic copy, which, by way of example, is a zinc oxide coated sheet of paper on which a toner image has been developed by electrophotography, has its image-bearing surface surface in contact with a transfer sheet. The transfer sheet, which may be made of plastic material, is substantially transparent to infrared light. Infrared light is then applied through the back surface of the transfer sheet whereby the toner image on the zinc oxide sheet preferentially heats up to a temperature at which it can melt the plastic sheet with which it is in contact. The heat is then removed, the toner image cools, and then, upon stripping the transfer sheet from the copy the toner image and the zinc oxide material adjacent thereto adheres to the transfer sheet.

The duplicating master now has the image areas of the electrophotographic copy raised above the surface thereof. These image areas have the property that they will preferentially absorb water-based inks whereas the nonimage areas repel water-based inks.

A technique for inking this duplicating master is described in an application by Schmutzler et al. Ser. No. 711,519, filed March 8, 1968, for a "Method and Means for Making a Pring Master, which is assigned to a common assignee. A liquid immiscible with water or water-miscible inks was applied to the nonimage portions of the printing master. Thereafter, a watermiscible-based ink was applied to the printing master and the ink was rejected by the preferentially coated nonimage areas and was accepted by the image areas. Alternatively, the master was first coated with a liquid immiscible with water which is then preferentially removed from the image areas to render them selectively attractive to the water-miscible printing ink.

OBJECTS AND SUMMARY OF THE INVENTION An object of this invention is to provide a simpler arrangement than heretofore employed for preferentially applying ink to the image areas of a printing master, in a manner to enable excellent prints to be obtained.

Another object of this invention is the provision of a onestep method and means for inking a printing master which will thereafter produce excellent prints.

Still another object of the present invention is the provision of a novel and unique method and means for inking a printing master with hydrophilic ink.

These and other objects of the invention are achieved by inking in the usual manner the rollers of a printing machine which employs a train of rollers between the ink reservoir and the final inking or form rollers which ink the printing master wrapped around the plate cylinder. In accordance with this invention, a hydrophobic liquid in small quantities is dropped on one of the rollers in the train, one which is sufficiently far back from the final inking roller so that the oil can be milled into the ink by the operation of the rollers in distributing the ink. The ink appears to be accepted by the image areas and rejected by the nonimage areas. The prints derived using this printing master are excellent.

The novel features of the invention are set forth with particularity in the appended claims. The invention will best be understood from the following description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is schematic diagram showing the roller arrangement for a printing press and indicating the roller upon which a hydrophobic liquid such as oil is dropped, in accordance with this invention.

' FIG. 2 represents another typical printing press roller arrangement and indicating the location which oil is dropped.

FIG. 3 indicates an oil distribution system in accordance with this invention.

FIG. 4 illustrates an addition which may be made to the inkfeeding system of a printing press, in accordance with this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic arrangement illustrative of the arrangement of rollers used in a commercially purchasable printing press. No modification is required in the arrangement of the rollers or in the manner in which printing is effectuated. A printing master 14 is wrapped around the plate cylinder 12 and is to receive ink from the form rollers 32, 34 in the usual manner. However, printing master 14 is preferentially wettable in the image areas by hydrophilic inks and can be made for example in accordance with the teachings of the application by this inventor, Ser. No. 668,262, filed June 12, 1967.

An ink supply 16, for the printing press, is adjacent the fountain roller 18, which receives ink from the ink supply container and transfers it to a ductor roller 20. The ductor roller 20 rotates and also oscillates reciprocally between the fountain roller and one of the distributing rollers 22, in well-known fashion. The distributing roller 22 rotates in contact with another distributing roller 24, which in turn rotates in contact with a vibrator roller 26. The vibrator roller oscillates reciprocally along its axis in order to assist in distributing the ink in a uniform coating. It in turn contacts another distributing roller 28. The distributing roller 28 rotates in contact with another distributing roller 30. The distributing roller 30 rotates in contact with two form rollers 32, 34. The two form rollers in turn rotate in contact with the plate cylinder 12. The plate cylinder 12 receives the uniformly distributed film of ink from the form rollers 32, 34.inking printing master 14. Paper 36, upon which it is desired that printing occur, is moved in contact with the printing master on the plate cylinder, in normal fashion.

The brief description of the rollers of the printing press and their cooperation with one another is thus far described is the usual arrangement. An illustration of a composition of watermiscible ink which was employed in the ink supply is as follows: 74 percent orange shellac solution (45 percent shellac, 2percent water) in propylene glycol, 8percent ethylenediameme 99 percent pure, and 18 percent carbon black (U- nited 30201.).

These ingredients are mixed and then ground thoroughly with a three roller mill.

In accordance with this invention, a hydrophobic liquid, such as oil, is dropped on the vibrator roller 26, employing an oil drop device 36. 'Details of the oil drop device are shown in FIG. 3. The oil that is dropped on the roller is mixed or milled into the ink by the successive rollers so that it is pretty uniformly distributed in the ink which is applied to the duplicating master. The quantity of oil which is used, is quite small. It varies with the viscosity of the ink, the heavier the viscosity the smaller the amount of oil that has to be used. For example, when an ink having an average viscosity of I20 poises is employed, for every five 8X10 prints, 0.03 cc. of oil is used. With a heavier viscosity of ink such as 300 poises, 0.02 cc. of oil is used.

The only critical part about the selection of the roller upon which the oil is to be dropped is that it be far enough back of the plate cylinder '50 that the oil is uniformly milled in with the ink. Two or more rollers back of the plate cylinder appear to be adequate. It is also desirable that the rollers contacting the one on which the oil is dropped as well as any additional rollers intended to mill the oil in the ink be made to engage adjacent rollers with some pressure to insure a uniform and thorough milling of the oil into the ink. By way of illustration, and not as a limitation, pressures on the order of 2530 pounds per linear inch have been used.

In FIG. 2, there is shown another ink roller lineup between the ink supply 40 and the final plate roller 42 around which the printing master 44 has been wrapped. Here, instead of the hydrophobic liquid being dropped on the vibrating roller 26, it is dropped on a distributing roller 46 from the oil drop device 48. Here the drops are dropped further down the chain of rollers than they were as shown in FIG. 1. The end results which were obtained are the same as in the first arrangement. In each case, pressures on the order of 25-30 pounds per linear inch were applied between the vibrator roll and a plurality of distributing rollers.

FIG. 3 shows the ink drop mechanism which is employed. The hydrophobic liquid in a reservoir 50 is fed to a pump 52. As illustrative but not limiting, the liquid may be Magic 400 oil, which is a kerosene fraction distilling between 398 F. and 435 F. The pump is actuated by a solenoid 54. The solenoid is actuated by an output of a counter 56. The counter in turn is advanced in response to a voltage pulse. The. voltage pulse is induced in a coil 58 which is connected to the input to the counter that has its closed-loop end adjacent to the side of the plate cylinder 12, for example. A permanent magnet 60 is attached-to the side of the plate cylinder so that during the course of its rotation it will cause the magnetic field of the magnet to be passed by the loop 58.

Since the plate cylinder rotates once for every print that is made, one can arrange to actuate the pump at a predetermined count of the counter whereby a predetermined amount of oil is dropped on the vibrator roller 26 for every predetermined number of prints which are made. By way of illustration, in an embodiment of the invention which was built, and satisfactorily operated, for every five prints or every fifth count of the counter 56, the solenoid 54 was operated. The roller on which the ink was dropped had an axial length of 10 inches and the diameter was 2%inches. However, the number of prints per operation of the pump is not critical so long as the proper quantity of oil is metered out.

ln order to insure as equal a distribution of oil over the roller as can be obtained as well as to properly meter the amount of oil delivered, a branching tree arrangement 60, was employed. As shown, successive branches of tubing are bifurcated or split in two, ending up with enough tubes, here shown as 16, to insure a fairly even ink drop distribution.

As indicated previously, very small quantities of oil, such as 0.02 cc. to 0.03 cc. for every five prints, are required. In order to control the oil drop device for that small a quantity of ink, the branch ends 62, 62' are formed of No. 26 hypodermic needles. These have a length of Be inch and a diameter of the opening of 0.003] inch. The pump 52 was made from a 2-cc. hypodermic syringe. The solenoid, when operated would meter out quantities of oil on the order of 0.1 cc.

The arrangement shown for metering out the oil is illustrative. Other arrangements may be employed such as to use a tube with a plurality of small holes, which tube is extended over the roller. A pump is used to pressurize the oil into the tube at the center and a baffle is placed in the tube to distribute the oil evenly to the holes through which the oil is dropped onto the roller.

Instead of using the described system consisting of a solenoid to actuate a pump in response to a signal magnetically derived from a roller on the printing press, one may use other arrangements. For example, cams driven in synchronism with the rollers of the printing press may be used to actuate the solenoid which drives the pump, and also may be used to actuate snap action valves between source of oil and pump and between pump and oil-distributing apparatus. The foregoing arrangements may be varied or changed by those skilled in the art without departing from the spirit and scope of this invention. Therefore, they should be considered as exemplary and not as limiting. i

A prefer-re way of feeding ink onto the fountain roller, in accordance with this invention, is to feed it under pressure so that it is forced onto the fountain roller. This may be achieved very simply in the manner shown in FIG. 4. The ink supply reservoir 40 which is fragmentally shown contains a supply of ink 64. A board 66 is floated on the ink. A weight 68 is placed on top of the board. The ink is quite viscous and so can support a weight. The weight selected is not so heavy as to sink when placed on the ink in the reservoir.

For example, a 2 pounds weight distributed over about 20 square inches was floated on ink having a viscosity of 200 poises :50.

There are obvious alternatives to floating a weight on the ink for applying ink under pressure to the fountain roller, which should still be considered as coming under the spirit of this invention and the scope of the claims. One of these may be to have a piston fit into the top of the reservoir. The piston is urged down on top of the ink either by air or hydraulic pressure. With a closed system, air pressure may be directly applied to the surface of the ink.

The reason for applying ink under pressure to the fountain roller is believed to be because it may happen that some of the oil dropped on a downstream roller may work its way back up the roller train to the fountain roller with the result that sufficient ink may not be taken up by the fountain roller to insure an even ink coating over the following rollers and thus the print quality may not be as good as desired. When the ink is forces onto the fountain roller this does not happen and print quality is excellent and remains excellent.

There has been accordingly described and shown herein a novel, useful and unique inking arrangement for an inking master of the type in which the image areas are preferentially coatable with water-miscible inks.

What is claimed is:

1. Apparatus for inking a printing master comprising:

ink-film-forming means including a train of a plurality of rollers for forming a water-miscible film of ink and applying it to the surface of said printing master, and

means for forcing ink with pressure exceeding atmospheric onto a first of said train of rollers,

means for milling predetermined amounts of a hydrophobic liquid into the film of ink formed by said train of rollers including:

a common pipe,

a plurality of successively bifurcated pipes extending from said common pipe to the surface of one of said train of rollers which is downstream from said first of said train of rollers for distributing a hydrophobic liquid from said common pipe through said plurality of said bifurcated pipe outputs over said one roller,

pump means for supplying a hydrophobic liquid to said common pipe responsive to a predetermined number of rotations of one of the rollers in said train. 2. Apparatus as recited in claim 1 wherein each of the plurality of outputs of said plurality of successively bifurcated pipes comprise a hollow needle. 

2. Apparatus as recited in claim 1 wherein each of the plurality of outputs of said plurality of successively bifurcated pipes comprise a hollow needle. 